National energy codes first appeared in the 70's as a response to the global energy crisis. The historically high oil prices and the resulting shock to the economy prompted a focus on how energy is used and, more importantly, how it may be wasted. Little attention was paid to the efficiency of a building's design or cost of operation before that time. The American Society of Heating Refrigeration and Air-Conditioning Engineers (ASHRAE) was at the forefront of energy code development, publishing the first industry standard in 1975. This standard has continued to evolve with input from the building community and as new technology became available. With a purpose to reduce energy use while still maintaining occupant comfort, ASHRAE Standard 90.1 has become the standard for design and construction in the United States and has a strong influence on commercial building designs throughout the world. The 2010 revision to this standard includes a new requirement to reduce energy consumption by controlling plug load circuits.